Beyond conventional ferromagnetism and antiferromagnetism, altermagnetism is a recently discovered unconventional magnetic phase characterized by time-reversal symmetry breaking and spin-split band structures in materials with zero net magnetization. This distinct magnetic phase not only enriches the understanding of fundamental physical concepts but also has profound impacts on condense-matter physics research and practical device applications. Spin-polarized band structures have been recently observed in semiconductors MnTe and MnTe2 with vanishing net magnetization, confirming the existence of this unconventional magnetic order. Metallic altermagnets have unique advantages for exploring novel physical phenomena related to low-energy quasiparticle excitations and for applications in spintronics as electrical conductivity in metals allows the direct manipulation of spin current through electric field. Here, through comprehensive characterization and analysis of the magnetic and electronic structures of KV2Se2O, we have unambiguously demonstrated a metallic room-temperature altermaget with d-wave spin-momentum locking. The highly anisotropic spin-polarized Fermi surfaces and the spin-density-wave order emerging in the altermagnetic phase make it an extraordinary platform for designing high-performance spintronic devices and studying many-body effects coupled with the unconventional magnetism.
@article{arxiv.2408.00320,
title = {Discovery of a metallic room-temperature d-wave altermagnet KV2Se2O},
author = {Bei Jiang and Mingzhe Hu and Jianli Bai and Ziyin Song and Chao Mu and Gexing Qu and Wan Li and Wenliang Zhu and Hanqi Pi and Zhongxu Wei and Yujie Sun and Yaobo Huang and Xiquan Zheng and Yingying Peng and Lunhua He and Shiliang Li and Jianlin Luo and Zheng Li and Genfu Chen and Hang Li and Hongming Weng and Tian Qian},
journal= {arXiv preprint arXiv:2408.00320},
year = {2025}
}